Pursuant to my original post, my associate passed his test with flying colours. Phew!!!!
It turns out I was guiding an ex-police superintendent.
The basis of my guidance was to concentrate on praising the associate for what he did well and not nit-picking on the faults. This approach seemed to work. In training for my own test, last year, my observer's approach was to find fault wherever he could (as does my trainer of me as an observer) and I needed the re-assurance of posters on this website such as In-Gear that I was doing things right.
I am endeavouring now with other like-minded members of my IAM group to get this sort of attitude changed.